Within the data storage system manufacturing industry, much attention is presently being focused on reducing head-to-disk clearance (i.e., flying height) as part of the effort to increase the storage capacity of data storage disks. It is generally desirable to reduce the head-to-disk clearance in order to increase the readback signal sensitivity of the transducer to typically weaker magnetic transitions associated with the higher recording density written on disks.
As the flying height of the head decreases, the slider assembly containing the head interacts much more frequently with the disk surface. As a result, the slider can accumulate a variety of contaminants as it passes in proximity to the surface of the disk. One phenomenon that has been recently discovered in the “Jami” problem, where contaminants (e.g., lubricants) are accumulated on the airbearing slider structure during normal operations, and subsequently dropped on the surface of the disk.
In most instances, these droplets of lubricant spread back onto the surface of the disk or are sheared off by air shear or the slider. However, in some instances, the head may be performing a write operation at the same time the slider encounters a lubricant droplet protruding from the surface of the disk. In this instance, a significant vertical excursion of the slider takes place, and the signal is not properly written to the surface of the disk. More specifically, the data is written with the head at an abnormally large head-disk spacing which causes incomplete overwrite of old data and results in a hard read error. Another deleterious type of Jami is the so-called “Dango Jami” which involves excitation of the airbearing slider at a resonance frequency. The resulting flying height modulation results in poor writing when the slider flying height is high.
As a result of the foregoing problems, there exists a need for an apparatus and method for performing in-situ detection of lubricant or other foreign material build-up on the trailing edge of a disk drive slider.